1. Field of the Invention
This invention relates to a spray-dried flour culture product and a method for its preparation. The product has unique growth promoting properties for viable cells of Lactobacillus sanfrancisco (L. sanfrancisco) such as those contained in prior art freeze-dried flour cultures and also contributes a safe and economical method of adjusting the pH in the first step of bakery application to one conductive to the rapid multiplication of the L. sanfransisco cells.
2. Brief Description of the Prior Art
The present inventor has described in the prior art (U.S. Pat. No. 4,140,800) a freeze-dried natural sour dough starter prepared by inoculating a flour-water-salt suspension with a natural mother or starter sponge containing strains of L. sanfrancisco and, after optimal growth is achieved, adding an appropriate stabilizer and freeze-drying. This prior art product also contains appreciable amounts of both lactic and acetic acids.
Indirect evidence was also presented in that prior art invention for the presence in the freeze-dried starter of an unidentified substance enhancing the growth of the bacteria when both were introduced into a new flour-water system. This evidence consisted principally of the finding that the higher the level of freeze-dried starter used in a new flour-water system, the more rapid was the multiplication of the bacteria, all other factors being equal. The nature and characteristics of this postulated growth-promoting substance were not elucidated nor are they presently known. In the present invention direct evidence is provided for the presence of this substance and its ability to survive the more drastic spray drying used in the present process. This was not anticipated in view of the absence of knowledge of the properties of this substance, making it impossible to predict its survival when exposed to both heat and air which are foreign to the prior art freeze-drying process.
The prior art (Gryczka, U.S. Pat. No. 3,963,835) describes a product prepared by fermentation of a flour-water system. However, in contrast to the present process, this product is prepared by fermentation with a pure culture of a selected bacteria which are first grown out on an artificial or synthetic medium (non-flour) and the cells separated and used as the seed or inoculum. In the present specification, the product of this prior art invention, marketed under the trade name "SAN FRAN" is shown not to contain significant quantities of the growth-promoting substance which is part of the composition of this present invention. Thus two basic differences may account for the uniqueness of the present product: (1) the mother sponge used as seed in the present process contains Torulopsis holmii (T. holmii) as well as L. sanfrancisco, and (2) these two microorganisms have been jointly cultivated in a flour culture for over 100 years. Both of these factors may contribute to the generation of the growth-promoting substance of the present invention.